1. Field of the Invention
This application relates to a disk drive. More particularly, this application relates to a base design that reduces vibration of the disks in the disk drive to improve track-following performance of the disk drive.
2. Description of the Related Art
A disk drive includes at least one disk with a magnetic medium deposited on at least one surface of the disk between an inner circumference and an outer circumference. The disk is mounted on and rotated by a spindle motor assembly, which includes a spindle motor bearing. The disk drive also includes a data transfer head that writes data onto the magnetic medium in concentric, generally circular tracks, and that reads data from the tracks written onto the magnetic medium. In most applications, the data transfer head is extended out over the magnetic medium by an actuator assembly that moves the head in an arcuate path with respect to the surface of the disk that has the magnetic medium. The actuator assembly usually includes an actuator arm and a head-gimbal assembly (HGA), which includes the data transfer head. The tracks on the disk are divided into sectors, which are presented to the data transfer head by the rotation of the disk. Each of the foregoing disk drive components at least partially is housed within an enclosure that usually includes a base and a cover.
The data transfer head is positioned over a selected track by a servo-system. The servo system includes servo data that is written onto the tracks. The data transfer head reads the servo data and generates a signal that indicates how close the head is to the center of a track based on the servo data. When the head is over the center of the track and follows it, the head is said to be track-following. When the head wanders from the centerline of the track, there is said to be track misregistration, or “TMR.” It is generally desirable to minimize TMR such that the disk drive is better able to perform data transfer.
One factor that tends to increase TMR is disk flutter, which has a number of known sources. For example, airflow generated by the rotation of the disk within the enclosure proximate the disk induces disk flutter. Increased TMR is not desirable because increased TMR limits track-to-track spacing (i.e., track pitch) and consequently limits areal density.